From: Bijan Parsia <bparsia@cs.man.ac.uk>

Date: Mon, 16 Feb 2009 18:58:11 +0000

Message-Id: <518271BC-46BC-493E-97BA-908136B762E7@cs.man.ac.uk>

Cc: Alan Ruttenberg <alanruttenberg@gmail.com>, public-rif-wg@w3.org, public-owl-wg@w3.org

To: Ivan Herman <ivan@w3.org>

Date: Mon, 16 Feb 2009 18:58:11 +0000

Message-Id: <518271BC-46BC-493E-97BA-908136B762E7@cs.man.ac.uk>

Cc: Alan Ruttenberg <alanruttenberg@gmail.com>, public-rif-wg@w3.org, public-owl-wg@w3.org

To: Ivan Herman <ivan@w3.org>

On 16 Feb 2009, at 17:48, Ivan Herman wrote: > Just an additional issue, though > > Alan Ruttenberg wrote: > [snip] >> In order for OWL to be precisely defined we need to base our >> specification on the mathematical properties of numbers, not the >> properties of implementations. Er...In order for OWL to be precisely defined we need to precise define OWL. Full stop. > Boris has reported major implementation issues regarding the > current setting. This is independent of the RIF coordination issue. > AFAIK, (and I may be wrong, sorry if that is the case) C&P also had > implementation issues. I definitely had problem on the RL > implementation side if I based it on an existing RDF environment. > > Ie, this may be one of those cases when implementation concerns may > have to have a priority. The mathematical structure that has floats disjoint from decimals is perfectly well behaved and fairly standard. There is a sensible mathematical structure in which rationals are disjoint from integers (e.g., let the integers be 0, plus the closure of 0 under the successor operator s and the minus sign (where -0 = 0); let the rationals be pairs <x, y> where x is an integer and y is an integer ! = 0; under this definition, no rational is an integer) > As I said on the RIF/OWL call, I also have serious concerns with > any RIF OWL incompatibilities, because there are applications that > use both rule systems (ie, RIF in future, hopefully) and OWL at the > same time. Those applications will have major issues. > > Ie: as far as I am concerned, it is not that clear cut... Well, for me, it is clear cut...pro disjointness :) DISJOINTNESS FOREVER!!!! The other point is also clear: The "mathematical properties" of a type called "float" esp. in relation to a type called "decimal" are not univocal. It depends on what we *want*. Personally, I think, and have always thought, that there is both user and implementation value in making them disjoint. I was proven right about implementation... ;) Cheers, Bijan.Received on Monday, 16 February 2009 18:54:40 UTC

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